Miners safety lamps. Historical artwork of two designs of Sir Humphry Davys miners safety lamps. They were invented in 1815 to prevent coal mining accidents, caused by explosions of methane- air mixtures ignited by the flames of miners candles. The design incorporates an oil burner enclosed in a copper gauze. The heat of the flame was effectively contained by conduction through the wires of the ga…

Your new EX II Speedlite from Canon can be the most powerful accessory in your camera bag! Understanding how the Speedlite’s controls work is important, and this DVD takes you through its operations, step by step. Your host, Tim Mantoa…